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Commit 42bba263 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
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perf probe: Allow wildcard for cached events 



Allo glob wildcard for reusing cached/SDT events. E.g.

  # perf probe -x /usr/lib64/libc-2.20.so -a %sdt_libc:\*

This example adds probes for all SDT in libc.
Note that the SDTs must have been scanned by perf buildid-cache.

Committer note:

Using it to check what of those SDT probes would take place when doing
a cargo run (rust):

  # trace --no-sys --event sdt_libc:* cargo run
     0.000 sdt_libc:setjmp:(7f326b69c4d1))
    28.423 sdt_libc:setjmp:(7f4b0a5364d1))
    29.000 sdt_libc:setjmp:(7f4b0a5364d1))
    88.597 sdt_libc:setjmp:(7fc01fd414d1))
    89.220 sdt_libc:setjmp:(7fc01fd414d1))
    95.501 sdt_libc:setjmp:(7f326b69c4d1))
     Running `target/debug/hello_world`
    97.110 sdt_libc:setjmp:(7f95e09234d1))
  Hello, world!
  #

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/146831791813.17065.17846564230840594888.stgit@devbox


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 05bf2c8a

tools/perf/util/probe-event.c

+103 −4
Original line number Diff line number Diff line
@@ -1204,7 +1204,7 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev) 
	ptr = strchr(*arg, ':');

	if (ptr) {

		*ptr = '\0';

		if (!is_c_func_name(*arg))

		if (!pev->sdt && !is_c_func_name(*arg))

			goto ng_name;

		pev->group = strdup(*arg);

		if (!pev->group)
@@ -1212,7 +1212,7 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev) 
		*arg = ptr + 1;

	} else

		pev->group = NULL;

	if (!is_c_func_name(*arg)) {

	if (!pev->sdt && !is_c_func_name(*arg)) {

ng_name:

		semantic_error("%s is bad for event name -it must "

			       "follow C symbol-naming rule.\n", *arg);
@@ -1644,6 +1644,7 @@ int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev) 
			ret = -ENOMEM;

			goto out;

		}

		tev->uprobes = (tp->module[0] == '/');

		p++;

	} else

		p = argv[1];
@@ -2518,7 +2519,7 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev, 
	int ret;



	/* If probe_event or trace_event already have the name, reuse it */

	if (pev->event)

	if (pev->event && !pev->sdt)

		event = pev->event;

	else if (tev->event)

		event = tev->event;
@@ -2531,7 +2532,7 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev, 
		else

			event = tev->point.realname;

	}

	if (pev->group)

	if (pev->group && !pev->sdt)

		group = pev->group;

	else if (tev->group)

		group = tev->group;
@@ -2894,6 +2895,100 @@ static int try_to_find_absolute_address(struct perf_probe_event *pev, 


bool __weak arch__prefers_symtab(void) { return false; }



/* Concatinate two arrays */

static void *memcat(void *a, size_t sz_a, void *b, size_t sz_b)

{

	void *ret;



	ret = malloc(sz_a + sz_b);

	if (ret) {

		memcpy(ret, a, sz_a);

		memcpy(ret + sz_a, b, sz_b);

	}

	return ret;

}



static int

concat_probe_trace_events(struct probe_trace_event **tevs, int *ntevs,

			  struct probe_trace_event **tevs2, int ntevs2)

{

	struct probe_trace_event *new_tevs;

	int ret = 0;



	if (ntevs == 0) {

		*tevs = *tevs2;

		*ntevs = ntevs2;

		*tevs2 = NULL;

		return 0;

	}



	if (*ntevs + ntevs2 > probe_conf.max_probes)

		ret = -E2BIG;

	else {

		/* Concatinate the array of probe_trace_event */

		new_tevs = memcat(*tevs, (*ntevs) * sizeof(**tevs),

				  *tevs2, ntevs2 * sizeof(**tevs2));

		if (!new_tevs)

			ret = -ENOMEM;

		else {

			free(*tevs);

			*tevs = new_tevs;

			*ntevs += ntevs2;

		}

	}

	if (ret < 0)

		clear_probe_trace_events(*tevs2, ntevs2);

	zfree(tevs2);



	return ret;

}



/*

 * Try to find probe_trace_event from given probe caches. Return the number

 * of cached events found, if an error occurs return the error.

 */

static int find_cached_events(struct perf_probe_event *pev,

			      struct probe_trace_event **tevs,

			      const char *target)

{

	struct probe_cache *cache;

	struct probe_cache_entry *entry;

	struct probe_trace_event *tmp_tevs = NULL;

	int ntevs = 0;

	int ret = 0;



	cache = probe_cache__new(target);

	/* Return 0 ("not found") if the target has no probe cache. */

	if (!cache)

		return 0;



	for_each_probe_cache_entry(entry, cache) {

		/* Skip the cache entry which has no name */

		if (!entry->pev.event || !entry->pev.group)

			continue;

		if ((!pev->group || strglobmatch(entry->pev.group, pev->group)) &&

		    strglobmatch(entry->pev.event, pev->event)) {

			ret = probe_cache_entry__get_event(entry, &tmp_tevs);

			if (ret > 0)

				ret = concat_probe_trace_events(tevs, &ntevs,

								&tmp_tevs, ret);

			if (ret < 0)

				break;

		}

	}

	probe_cache__delete(cache);

	if (ret < 0) {

		clear_probe_trace_events(*tevs, ntevs);

		zfree(tevs);

	} else {

		ret = ntevs;

		if (ntevs > 0 && target && target[0] == '/')

			pev->uprobes = true;

	}



	return ret;

}



static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,

					      struct probe_trace_event **tevs)

{
@@ -2903,6 +2998,10 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev, 
	struct str_node *node;

	int ret, i;



	if (pev->sdt)

		/* For SDT/cached events, we use special search functions */

		return find_cached_events(pev, tevs, pev->target);



	cache = probe_cache__new(pev->target);

	if (!cache)

		return 0;

tools/perf/util/probe-file.c

+32 −6
Original line number Diff line number Diff line
@@ -362,13 +362,38 @@ probe_cache_entry__new(struct perf_probe_event *pev) 
	return entry;

}



/* For the kernel probe caches, pass target = NULL */

int probe_cache_entry__get_event(struct probe_cache_entry *entry,

				 struct probe_trace_event **tevs)

{

	struct probe_trace_event *tev;

	struct str_node *node;

	int ret, i;



	ret = strlist__nr_entries(entry->tevlist);

	if (ret > probe_conf.max_probes)

		return -E2BIG;



	*tevs = zalloc(ret * sizeof(*tev));

	if (!*tevs)

		return -ENOMEM;



	i = 0;

	strlist__for_each_entry(node, entry->tevlist) {

		tev = &(*tevs)[i++];

		ret = parse_probe_trace_command(node->s, tev);

		if (ret < 0)

			break;

	}

	return i;

}



/* For the kernel probe caches, pass target = NULL or DSO__NAME_KALLSYMS */

static int probe_cache__open(struct probe_cache *pcache, const char *target)

{

	char cpath[PATH_MAX];

	char sbuildid[SBUILD_ID_SIZE];

	char *dir_name = NULL;

	bool is_kallsyms = !target;

	bool is_kallsyms = false;

	int ret, fd;



	if (target && build_id_cache__cached(target)) {
@@ -378,12 +403,13 @@ static int probe_cache__open(struct probe_cache *pcache, const char *target) 
		goto found;

	}



	if (target)

		ret = filename__sprintf_build_id(target, sbuildid);

	else {

	if (!target || !strcmp(target, DSO__NAME_KALLSYMS)) {

		target = DSO__NAME_KALLSYMS;

		is_kallsyms = true;

		ret = sysfs__sprintf_build_id("/", sbuildid);

	}

	} else

		ret = filename__sprintf_build_id(target, sbuildid);



	if (ret < 0) {

		pr_debug("Failed to get build-id from %s.\n", target);

		return ret;

tools/perf/util/probe-file.h

+3 −0
Original line number Diff line number Diff line
@@ -34,6 +34,9 @@ int probe_file__get_events(int fd, struct strfilter *filter, 
				  struct strlist *plist);

int probe_file__del_strlist(int fd, struct strlist *namelist);



int probe_cache_entry__get_event(struct probe_cache_entry *entry,

				 struct probe_trace_event **tevs);



struct probe_cache *probe_cache__new(const char *target);

int probe_cache__add_entry(struct probe_cache *pcache,

			   struct perf_probe_event *pev,